The invention relates to a latch for a door or a flap comprising a locking mechanism that has a catch and a pawl for locking the catch. Such a latch is disclosed in DE 103 20 457 A1. The invention also relates to a method for producing a plurality of said latches.
The aforementioned latch serves for temporary locking of openings in motor vehicles or buildings with the aid of doors or flaps. In the closed state of such a latch, the catch extends around an, in particular, bow-shaped latch bolt, which in case of a motor vehicle is generally fixed to the car body. Where as a result of being pivoted with the aid of the latch bolt, the catch is moved from an open into a closed position, the catch is then locked by means of the pawl. A blocking face of the pawl then rests against a blocking face of the catch, preventing the catch from being turned back in the direction of the open position. When in the closed position, the latch bolt can no longer leave the locking mechanism.
To open the mechanism, the pawl must be moved out of its detent position. Once the pawl has been moved out of its detent position, the catch turns into the direction of its open position. In the opened position of the catch and thus in the opened position of the locking mechanism, the latch bolt can leave the latch. The door or flap can then be opened again.
After the pawl has moved out of its detent position, the catch can be turned in the direction of the open position by a sealing pressure of the respective door or flap or by a pretensioned spring. Such a rotation can also be caused by the latch bolt being pulled out of the locking mechanism.
In some latches, the catch has two different detent positions. In this case, the catch can then be first locked in a so-called pre-ratchet position and then in the so-called main ratchet position by continuing rotation in the closing direction. Although in the pre-ratchet position a latch bolt can no longer leave the locking mechanism, a respective door or flap is, however, not fully closed. Such a door or flap is only fully closed when the catch is turned up to the main ratchet position and is locked in this position.
The latch can contain a blocking lever able to block a pawl when the pawl locks the catch. In order to open such a locking mechanism, the blocking lever must first be moved out of its blocking position.
In order to facilitate particularly easy opening of a latch, the catch can introduce an opening moment into the pawl in the locked state. The opening moment can cause the pawl to be moved out of its detent position. In such a latch, unwanted moving of the blocking lever out of its detent position is prevented. If the blocking lever is moved out of its blocking position, the latch then opens automatically.
An actuating means is provided for opening the latch. Upon activating the actuating means the locking mechanism is opened. A handle of a door or of a flap can be part of the actuating means. This handle is generally connected to the actuating lever of the latch by means of rods or a Bowden cable. Upon actuating the handle, the rods or the Bowden cable pivot the actuating lever of the latch in such a way that the latch opens.
Latches of motor vehicles are regularly equipped with a central locking (see e.g. DE 4108561 A1) and/or an anti-theft device (see e.g. DE 10 2011 018 512 A1). To lock a side door latch and engage an anti-theft device, respective mechanisms are provided, generating a rotational or linear movement and thus locking or unlocking the latch or engaging or releasing the anti-theft device.
For safety reasons, any movement of the locking or anti-theft device should be prevented in the event of an accident, i.e. movement from a locked into an unlocked position or, in case of the anti-theft device, movement from an engaged into a released position.
In order to protect a locking means or anti-theft device against movement into another position during an accident or crash, an arrangement can be provided in which one leg of a spring has to me moved against the force of the spring in order to be able to move the position of a latch or antitheft device. The greater the force required for moving such a spring leg, the greater the required acceleration in the event of a crash in order to be able to change the position of an anti-theft device or of a locking mechanism. By using the correct spring force it can thus be achieved that accelerations of 30 g or up to 55 g cannot change the position of an anti-theft device or of a central locking. g stands for gravitational acceleration. The leg spring secures the position of a locking mechanism or the position of an anti-theft device in case of high accelerations, as experienced in the event of a crash.
The position of a locking mechanism or anti-theft device is regularly changed with the aid of a motor, when required. The existence of a position securing system requires a respective motor power to overcome the position securing system, i.e. to move the spring leg in the said example.